A typical XANES spectrum is shown in fig. 1a. The
spectrum was acquired over the black spot encircled in the
47
image in fig. 1b (which is an X-ray fluorescence map of the
sea urchin larva, recorded at 3.56 keV). The XANES spectra
show that the black spots are associated with the presence of
agglomerated AgNPs in the sea urchin larvae.